Two-stage throttle valve for an automatic transmission

ABSTRACT

A THROTTLE VALVE SYSTEM FOR AN AUTOMATIC POWER TRANSMISSION MECHANISM IN AN AUTOMOTIVE VEHICLE DRIVELINE HAVING AN INTERNAL COMBUSTION ENGINE WITH AN EXHAUST GAS RECIRCULATION CONTROL, SAID THROTTLE VALVE SYSTEM BEING ADAPTED TO PRODUCE A PRESSURE SIGNAL THAT IS RELATED FUNCTIONALLY TO THE MAGNITUDE OF THE ENGINE TORQUE AND INCLUDING A DIAPHRAGM ACTUATOR THAT IS SUBJECTED TO ENGINE INTAKE MANIFOLD PRESSURE AND A SECONDARY THROTTLE VALVE THAT   MODIFIES THE VALVE ACTUATING FORCES OF THE DIAPHRAGM ACTUATOR TO COMPENSATE FOR THE EFFECT OF THE EXHAUST GAS RECIRCULATION CONTROL SYSTEM ON THE ENGINE INTAKE MANIFOLD, THEREBY TENDING TO MAINTAIN THE DESIRED RLATIONSHIP BETWEEN ENGINE TORQUE AND THE OUTPUT PRESSURE SIGNAL OF THE THROTTLE VALVE SYSTEM.

March 6, 1973 E, F, JAGDMANN ET AL 3,719,107

TWO-STAGE THROTTLE VALVE FOR AN AUTOMATIC TRANSMISSION 3 Sheets-Sheet 1Filed Nov. 2. 1971 March 6. 1973 E, F, AG MANN Em 3,719,107

TWO-STAGE THROTTLE VALVE FOR AN AUTOMATIC TRANSMISSION March 6, 1973 EF. JAGDMANN ,iT AL 3,719,107

TWO-STAGE THROTTLE VALVE FOR AN AUTOMATIC TRANSMISSION United "StatesPatent O F 3 719,107 TWO-STAGE THROTTLE VALVE FOR AN AUTOMATICTRANSMISSION Edwin F. Jagdmann, Northville, and George E. Lemieux,

Livonia, Mich., assignors to Ford Motor Company,

Dearborn, Mich.

Filed Nov. 2, 1971, Ser. No. 195,030 Int. Cl. B601; 21/02 US. Cl. 748434 Claims ABSTRACT OF THE DISCLOSURE A throttle valve system for anautomatic power transmission mechanism in an automotive vehicledriveline having an internal combustion engine with an exhaust gasrecirculation control, said throttle valve system being adapted toproduce a pressure signal that is related func tionally to the magnitudeof the engine torque and including a diaphragm actuator that issubjected to engine intake manifold pressure and a secondary throttlevalve that modifies the valve actuating forces of the diaphragm actuatorto compensate for the effect of the exhaust gas recirculation controlsystem on the engine intake manifold, thereby tending to maintain thedesired relationship between engine torque and the output pressuresignal of the throttle valve system.

GENERAL DESCRIPTION OF THE INVENTION The improved throttle valve systemof our invention is adapted to be used in the driveline of an automotivevehicle having an internal combustion engine with an airfuel mixtureintake manifold controlled by a carburetor throttle valve. Inconventional control circuits for transmission in such drivelines it iscommon practice to use a transmission throttle valve having a diaphragmactuator that is subjected to engine intake manifold pressure. Themanifold pressure forces acting on the diaphragm of the actuator aretransmitted to a throttle pressure modulator valve element. Controlpressure from an engine driven pump is regulated and the regulatedpressure is distributed to the throttle valve system where it ismodulated by the throttle valve element. Upon an increase in the engineintake manifold pressure, which would correspond to an increase inengine torque, the output signal of the throttle valve is increased.This signal is used to initiate speed ratio changes. It is used also tovary the output pressure of the main regulator valve for the circuit sothat a high regulated control pressure will be maintained by theregulator valve system when the engine manifold presure is high. It willreduce the control pressure when the engine is operated at low torque,which would correspond to a reduced manifold pressure.

In certain exhaust gas emission control devices used with internalcombustion engines, a portion of the exhaust gases under specificoperating conditions is recirculated to the engine intake manifoldsystem where it is cycled a second time through the combustion process.This reduces the engine manifold vacuum, but this loss in vacuum is notaccompanied by the usual increase in engine torque. When compensationthen is made for the effect of the exhaust gas recirculation controls,the output pressure signal from the transmission throttle valve systemwill produce a changed shift timing signal on the shift valves 3,719,107Patented Mar. 6, 1973 of the control circuit. It will also cause anundesirable increase in circuit pressure. These influences causeretarded ratio upshifts during the acceleration period of the vehicleand relatively rough or harsh ratio changes due to the excessive controlpressure that is made available to the pressure operated servos for thetransmission clutches and brakes.

The improvement of our invention compensates for the effect of theexhaust gas recirculation controls on the output pressure signal of thethrottle valve system. This is accomplished by providing in the throttlevalve system a secondary valve element that acts upon the primarypressure modulating valve element of the throttle valve system with aprecalibrated force. Provision is made for establishing fluidcommunication between the high pressure portion of the 'valve system andthe secondary valve element when the exhaust gas recirculation controlsare triggered. This changes the net forces acting on the secondary valveand hence the primary throttle valve actuating forces are also changed,thereby causing a different calibration for the throttle valve systemduring those instances when the exhaust gas recirculation controls areeffective. The optimum ratio shift performance thus is maintained forthe entire range of operating conditions of the vehicle engine.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING FIG. 1 shows inschematic form a transmission gearing arrangement with clutches andbrakes adapted to be controlled by fluid pressure operated servos whichform a part of our improved control system.

FIG. 2 is a schematic representation of a control valve system embodyingthe improvements of our invention for use with a transmission mechanismof the type shown in FIG. 1.

FIG. 3 is a subassembly view of the throttle valve system included inthe schematic circuit of FIG. 2.

FIG. 4 is a graph showing the relationship between manifold pressure andthe output pressure signal of the throttle valve system when the exhaustgas recirculation control is effective as well as when it isineffective.

PARTICULAR DESCRIPTION OF THE INVENTION In FIG. 2 numeral 10 designatesthe crankshaft of an internal combustion engine 12 in an automotivevehicle driveline. The engine includes a throttle valve controlledcarburetor 14, an air-fuel mixture intake manifold 16 and a combustiongas exhaust gas manifold 18. An exhaust gas recirculation control valve20 is connected at one side to a control pressure line 22. It includes asolenoid actuated shift valve which is adapted to control distributionof pressure from line 22 to line 24, the latter extending to throttlevalve system 26. The solenoid actuated shift valve includes a circuithaving an electric switch 28, which is actuated by engine intakemanifold pressure variations. Switch 28 is connected to the intakemanifold through passage 30.

Crankshaft 10 is connected to the impeller 32 of a hydrokinetic torqueconverter 34. When the switch 28 is actuated, the exhaust gasrecirculation control 20 is activated and this in turn activates thesolenoid actuated shift valve Which is identified in FIG. 3 by referencecharacter 36.

Converter 34, in addition to the impeller 32, includes a bladed turbine38 and a bladed stator 40. The impeller, the stator and the turbine arearranged in toroidal fluid flow relationship in the usual fashion.Turbine 38 is connected drivably to turbine shaft 42, which serves as apower input shaft for the gearing illustrated schematically in FIG. 1.

A positive displacement pump 44 is connected drivably to the impeller32. The output pressure passage for the pump is in communication withpassage 22.

The transmission gearing, shown in FIG. 1, includes a first simpleplanetary gear unit 46 and a second simple planetary gear unit 48.Direct-and-reverse clutch 50 may be engaged and released by a fluidpressure operated clutch servo 52 to establish and diseastablish adriving connection between driven shaft 42 and drive shell 54. Shell 54is connected directly to sun gear 56, which is common to both of thesimple planetary gear units 46 and 48. Gear unit 46 includes, inaddition to the sun gear 56, a ring gear 58, a carrier 60 and planetpinions 62 journalled rotatably on the carrier 60 in meshing engagementwith the ring gear '58 and sun gear 56. Carrier 60 is connected drivablyto power output shaft 64.

Gear unit 48 includes, in addition to the sun gear 56, a ring gear 66,carrier 68 and planet pinions 70, the latter being journalled on thecarrier 68 in meshing engagement with ring gear 66 and sun gear 56. Ringgear 66 is connected directly to the power output shaft 64. Carrier 68is connected to or partly defines a brake drum about which is positioneda low-and-reverse brake band 72. Carrier 68 is adapted to be anchored tothe transmission housing 74 through an overrunning brake 76 duringoperation in the low speed ratio in the automatic drive range.

A forward drive clutch 78 is adapted to establish and disestablish adriving connection between shaft 42 and ring gear 58. Clutch 78 isactuated by a fluid pressure operated servo 80. The clutch 50 defines abrake drum about which is positioned an intermediate speed ratio brakeband 82. Brake band 82 is applied and released by fluid pressureoperated servo 84. Brake band 72 is applied and released by a fluidpressure operated reverseand-low servo 86.

A compound governor valve assembly 88 is connected drivably to the poweroutput shaft 72. Shaft 72 is connected drivably to road wheels 90through a suitable driveshaft and difierential-and-axle assembly.

The gearing mechanism of FIG. 1 is capable of establishing three forwarddrive speed ratios and a single reverse speed ratio. To establish thelowest forward drive speed ratio, the forward clutch 78 is applied. Itremains applied during operation in each of the forward driving ratios.Clutch 78 then connects the driven shaft 42 to the ring gear 58. Theresistance to rotation offered by the carrier 60 causes a reversedriving torque on the sun gear 56. The torque then is reversed again asit passes through and is multiplied by gear unit 48. Carrier 68 acts asa reaction member since reaction torque on the carrier is transferredthrough the overrunning brake 76 to the stationary housing. A positiveforward driving torque on the ring gear 66 complements the forwarddriving torque on the carrier 60.

To establish intermediate speed ratio operation, intermediate speedratio brake band 82 is applied while the clutch 78 remains applied. Thisanchors the sun gear 56. With the ring gear 58 acting as a torque inputelement of the gearing, sun gear 56 acts as a reaction member andcarrier 60 acts as a driven member. Output shaft 64 then is driven at anincreased speed ratio greater than the lowest speed ratio but less thanunity. overrunning brake 76 freewheels under these conditions.

Direct drive, high speed ratio operation is achieved by engagingsimultaneously both clutches T8 and 50 and releasing both brakes. All ofthe elements of the gearing then are locked together for rotation inunison.

Brake band 72 is engaged during continuous low speed ratio'operation andduring reverse drive. It is capable of transferring reaction torqueunder these driving conditions from the carrier 68 to the housing.

Direct and reverse drive clutch 50 is applied and brake band 72 isapplied. Clutch 78 is released and brake band 82 is released. Torquefrom shaft 42 then is distributed through the clutch 50 to the sun gear56. With the carrier 68 acting as a reaction member, ring gear 66 isdriven in a reverse direction. The reverse motion of ring gear 66 istransferred to the output shaft 64.

The actuation and release of the clutches and the brakes is achieved bythe control system shown in FIG. 2. The clutches and brakes are appliedby fluid pressure operated servos which receive control pressure frompump 30. This pressure is regulated by a main pressure regulator valve92. The regulated line pressure is distributed from the regulator valveto a driver-operated manual valve 94. This valve can be moved by theoperator to any one of several drive range positions. These areindicated by the symbols R, N, D, 2 and 1, which respectively identifythe reverse position, the neutral position, the automatic drive rangeposition, intermediate speed ratio drive position and low speed ratiodrive position. When the manual valve is shifted to the R position or tothe 1 position, passage 96, extending from the output side of the mainregulator valve 92, is connected to passage 98. This in turn extends tothe reverseand-low servo 86.

Manual valve 94 connects passage 96 with passage 100 whenever it assumesone of the forward driving range positions. This passage 100 extends inturn to direct-andreverse clutch 50.

When the manual valve is shifted to the 2 position, passage 96 isconnected to passage 102, which extends to the apply side of theintermediate servo 84. This servo includes a piston 10-4 situated in acylinder 106. It defines a pressure chamber on either side of thecylinder. When both pressure chambers are pressurized, the brake isreleased.

If the left-hand apply pressure chamber is pressurized, the brake isapplied. Thus, during automatic operation of the control valve system,the intermediate speed ratio brake band may be applied and released byselectively pressurizing and exhausting the release pressure chamber ofthe servo 84. Pressure is distributed to the release side of the servo84 through a 1-2 shift valve 108. This valve receives control pressurefrom the manual valve 94 through passage 110. It is triggered to theupshift position by the force of governor pressure distributed to oneside of the shift valve through passage 110, which in turn extends tothe speed signal pressure source which is the governor 8 8. The upshiftsignal from the governor 88 is opposed by a downshift throttle valvesignal from the TV boost valve 112. Valve 112 is applied when an inputsignal through passage 114 extends to throttle valve assembly 26. Thisassembly will be described with reference to FIG. 3.

Valve 112 receives the output signal from 'valve system 26 to modulatecontrol pressure distributed to it from passage 22. This amplifies thepressure signal that is an indicator of engine torque so that enginemanifold pressure may be relied upon as an accurate indicator of enginetorque demand.

Line pressure is distributed also to 2-3 shift valve 116 through passage118, the latter communicating with the manual valve. Passage 118 ispressurized during operation in the automatic drive range position D.Governor pressure from passage acts on one side of the 23 shift valve116, and the output signal of the TV boost valve acts in the oppositedirection. The signal is distributed to the 2-3 shift valve throughpass-age 120. When an upshift occurs in response to opposing influencesof the pressures in passages 120 and 110, pressure is distributed frompassage 118 to passage 122, which extends to direct-and-reverse clutch50.

The output signal for valve 26 is distributed also to cutback valve 124through passage 114. One side of valve 124 is subjected to the governorpressure in passage 110. After a predetermined output speed is achieved,valve 124 is triggered by the governor pressure to distribute pressurefrom passage 114 to passage 126, which in turn extends to the mainregulator valve. The cutback valve 124, by selectively pressurizing andexhausting passage 126, causes the main regulator valve 92 to regulateat a higher pressure at lower vehicle speeds-and at a relatively lowpressure at higher vehicle speeds for any given throttle pressure.

It is apparent from FIG. 2 that the output signal of valve system 26 isused both for controlling the shift points during automatic speed ratiochanges as well as the circuit pressure level.

FIG. 3 shows in more detail the characteristics of the valve system 26.It includes a secondary valve 128 and a primary valve 130. The primaryvalve 130 includes a pair of spaced valve lands 132 and 134. These areslidably situated in valve chamber 136 which is formed with ports thatregister with the lands. A first port 138 communicates with theregulated line pressure passage 96. A third valve land 140 of relativelylarge diameter defines with the land 132 a differential area thatcommunicates with port 142. This may be pressurized with line pressurethat is distributed to passage 100 during reverse drive operationthereby providing for an augmentation in the magnitude of the outputpressure signal of valve system 26 during reverse drive which producesan augmentation of the main regulator valve pressure.

Passage 114 communicates with the output pressure port of the valve 130,which receives modulated pressure from the valve 130. This modulatedpressure is distributed to the left-hand side of the land 140 to providethe necessary pressure feedback. The force acting on the valve 130 toproduce modulation is provided by actuator spring 144 located inactuator housing 146. A flexible diaphragm 148 is located in the housing146, and it cooperates with the housing 146 to define a manifoldpressure chamber 150. A force transmitting stem 152 connectsmechanically the valve 130 with the diaphragm 148. The left-hand side ofthe diaphragm 148 is exposed to atmospheric pressure.

A vacuum pressure fitting 154 establishes communication between chamber150 and manifold pressure passage 156 shown in FIG. 1. Passage 156extends to the engine intake manifold at a location on the downstreamside of the carburetor throttle illustrated schematically in FIG. 1 byreference character 158.

The secondary valve 128 includes a pair of valve lands 160 and 162.These define a differential area that is in fluid communication withpassage 164. That area is pressurized with line pressure, which isdistributed to it through solenoid actuated shift valve 166 when valve166 is deactuated. It is deactivated whenever the EGR system isdeactivated. If the EGR system is effective, the valve 166 connectspassage 164 to the exhaust passage illustrated schematically at 168.

The right-hand side of the land 162 is exposed to the feedback pressurein passage 114. This pressure complements the pressure in passage 164 tooppose the force of valve spring 170. Valve 128 engages the left-handend of the valve 130. Thus when passage 164 is exhausted, the force ofspring 170 opposes the force of spring 144. This reduces the magnitudeof the throttle valve signal. The amount of the reduction is calibratedto correspond to the reduction in engine torque that results from theintroduction of exhaust gas through the exhaust gas recirculation systeminto the intake manifold. The calibration is achieved by controlling thespring rate of spring 170 and by controlling the diameter of land 162,which is exposed to throttle pressure in passage 114.

The variation in engine intake manifold pressure, which occurs for eachvalue of the throttle valve signal, is illustrated by curve A in FIG. 4.This curve A shows a relationship between these two variables when theEGR system is deactivated. Curve B, on the other hand, represents therelationship between these two variables when the EGR system'isactuated. The change from curve A to curve B in FIG. 4 is achieved bytriggering the solenoid actuated shift valve, which either activates ordeactivates the secondary throttle valve 138..

Having thus described a preferred embodiment of our invention, what weclaim and desire to secure by U.S. Letters Patent is:

1. A control valve circuit for an automatic power transmission mechanismin an automotive vehicle driveline having an internal combustion enginewith an air-fuel mixture intake manifold, said transmission comprisinggearing adapted to establish multiple torque delivery paths between adriving member and a driven member, fluid pressure operated clutches andbrakes for controlling the relative motion of elements of said gearing,a fluid pressure source, conduit structure connecting said pressuresource to said clutches and brakes, shift valve means in said conduitstructure for establishing and disestablishing a fluid connectionbetween said source and said clutches and brakes. a source of the speedsignal pressure drivably connected to a driven member, a pressure signalpassage extending from said signal source to said shift valve means forimposing on the latter an upshifting tendency, a throttle valve systemconnected hydraulically to said shift valve means for imposing on thelatter a downshifting tendency, a main pressure regulator valve meansfor regulating the pressure supplied by said pressure source, saidthrottle valve system including a flexible diaphragm defining in part amanifold pressure chamber, a manifold pressure passage connecting theintake manifold of said engine with said manifold pressure chamber,spring means acting on said diaphragm whereby changes in manifoldpressure cause deflection of said diaphragm, a modulator valve elementin said throttle valve system connected mechanically to said flexiblediaphragm, means for supplying pressure from a high pressure portion ofsaid circuit to said modulator valve, modulated output pressure of saidmodulator valve being related in magnitude to the engine intake manifoldpressure, and a secondary throttle valve in said throttle valve system,said secondary throttle valve including a valve spring acting on it inone direction, a fluid pressure area on said secondary throttle valve,the force created by pressure on said area urges said secondary throttlevalve in the opposite direction, the net forces acting on said secondarythrottle valve being distributed to said modulator valve element wherebythe modulating characteristics of the latter may be changed, said enginehaving exhaust gas recirculation control whereby engine exhaustemissions may be recirculated to the intake manifold, said controlincluding an automatically operated shift valve in fluid communicationwith said pressure area on said secondary throttle valve whereby thepressure forces on said secondary throttle valve may be applied andreleased in response to the activation and deactivation of said control.

2. The combination as set forth in claim 1 wherein the pressure area onthe secondary throttle valve element is in fluid communication with ahigh pressure portion of said circuit whereby said secondary throttlevalve element is urged in said opposite direction against the opposingforce of the spring acting thereon thereby interrupting the transfer offorces from said secondary throttle valve element to said modulatorvalve element.

3. The combination as set forth in claim 1 wherein said exhaust gasrecirculation control includes a solenoid actuated shift valve, saidsolenoid actuated shift valve defining in part a fluid connectionbetween a high pressure region of said circuit and said pressure area onsaid secondary valve element, said solenoid actuated shift valve 7 beingactuated to exhaust the pressure area on said secondary valve elementwhen the exhaust gas recirculation control is activated whereby thespring acting on said secondary valve element opposes the spring actingon said flexible diaphragm.

4. The combination as set forth in claim 2 wherein said exhaust gasrecirculation control includes a solenoid actuated shift valve, saidsolenoid actuated shift valve defining in part a fluid connection(between said high pressure region of said circuit and said pressurearea on said secondary valve element, said solenoid actuated shift valvebeing actuated to exhaust the pressure area on said secondary valveelement when the exhaust gas recirculation control is activated wherebythe spring acting on said secondary valve element opposes the springacting on said flexible diaphragm.

References Cited UNITED STATES PATENTS 3,688,606, 9/1972 Lemieux et a1.74-863 CHARLES J. MYHR-E, Primary Examiner m T. C. PERRY, AssistantExaminer U .8. Cl. X.R. 74864

